A number of technologies have been developed for stereovision, sometimes referred to as 3D or 3D-vision. They may be divided into 2 large classes: glasses-based and non-glasses based. The advantage of non-glasses technology is that the viewer does not need to wear glasses. The downside frequently is that the “sweet spot”—the range of head motion—is limited to +/−˜5 degrees. The use of glasses for watching motion video is largely based on simultaneous or sequential projections of two images on the screen.
The following are some of the more widely used glasses systems. Shutter glass systems are widely seen in European markets, for example the XpanD brand. Right and left images are projected onto the screen time sequentially. The liquid crystal display (LCD) shutters on the glasses are synchronized to the projected images and ensure that a viewer's right eye sees the “right” image only and the left eye only sees the “left” image. Polarization glasses include real D circularly polarized glasses of opposite “handedness” for right and left glasses. This system is most prominently promoted by the IMAX technology and supported by The Walt Disney Studios, DreamWorks Studios, and other studios. The Geowall Consortium uses a linear polarization system. Color filter glasses include the following: red/cyan anaglyph; and Dolby Laboratories 3D (color-wheel and multiple-bandpass filters).